Machines of the type described above are used in agriculture to cut stalk-like crops, e.g. corn plants, from the soil of a field and convey them to a field chopper borne on the machine, in which chopper the plants are chopped and are discharged to a storage container on a trailer. As a rule, such machines have a number of laterally disposed cutting and intake mechanisms, each in the form of an elongated rotor rotating around a vertical axis, which rotors operate independently of the rows and which have recesses distributed around their edges, which recesses accommodate the plant stalks. Such cutting and intake mechanisms have mowing wheels disposed under said rotors, which mowing wheels serve to cut off the plant stalks generally at ground level.
In numerous such machines (DE 36 23 380 A, U.S. Pat. No. 5,651,243 A, U.S. Pat. No. 5,845,472, U.S. Pat. No. 6,775,967, US 2003/0101703, when in harvesting mode, the cutting and intake mechanisms closest to the longitudinally extending mid-plane of the machine rotate such that the plants are first transported toward said longitudinal mid-plane of the machine and then rearward in the direction of the intake channel of the field chopper. In these machines, rhomboidally shaped guide elements are employed between the cutting and intake mechanisms which are close to the longitudinal mid-plane, which guide elements extend upward from the bottom of the machine, ahead of, between, and/or rearward of the cutting and intake mechanisms, in order to guide the stream of material in this region and to prevent the development of a persistent free space in the region ahead of the intake channel of the field chopper, in which free space the plants are not supported and thus topple on their sides. These guide elements are adjusted to the shape of the neighboring cutting and intake mechanisms, and have a generally pointed structure at their forward and rear ends. The guide elements do not extend above the cutting and intake mechanism, and thus the upper parts of the plants are not supported.
A particular drawback of these machines is that the cutting and intake mechanisms close to the longitudinal mid-plane rotate in a direction which does not allow transport of the plants inwardly at the rear sides of said mechanisms; accordingly, a separate conveying means is needed in order to transport plants from the more outwardly disposed cutting and intake mechanisms toward the center of the machine. In U.S. Pat. No. 5,845,472, e.g., a screw conveyor is employed, whereas in the above-cited European patents so-called transverse conveying drums are employed. These separate conveyors are costly, and increase the weight and length of the machine in the direction of travel. In DE 36 23 380 A, plants incoming from outer regions are conveyed to the front side of the cutting and intake mechanisms; such machines have not proven successful in practice.
Machines have also been described in which, in a harvesting mode, the cutting and intake mechanisms close to the longitudinal mid-plane rotate such that the plants are first transported forwardly in the direction of the longitudinal mid-plane and outwardly. Examples occur in DE 195 27 607 A, DE 198 56 444 A, U.S. Pat. No. 5,722,225, U.S. Pat. No. 6,502,378, U.S. Pat. No. 6,658,832, and GB 2,012,154 A. This rotational direction makes it possible to transport the plants incoming from the outer regions via the rear sides of the cutting and intake mechanisms which are close to the longitudinal mid-plane. This transporting of plants can be supplemented by additional conveying elements in the form of transverse conveying drums (see the cited EP patents) or rotationally driven discharging wheels (DE 195 27 607 A) disposed in the region of the housings of the cutting and intake mechanisms. Also, transverse conveyors which operate independently from the cutting and intake mechanisms may be provided, as in DE 198 56 444 A.
In the machines according to DE 195 27 607 A, DE 198 56 444 A, and U.S. Pat. No. 5,722,225, guide elements are also provided, disposed between the cutting and intake mechanisms which are close to the longitudinal mid-plane, which guide elements extend rearwardly to a point slightly ahead of the intake channel of the field chopper. These guide elements are not higher than the conveying channel. Thus, they do not provide any support to the upper parts of the plants.
U.S. Pat. No. 6,502,378 proposes to provide a drivable conveying device in the center of the machine above the central cutting and intake mechanisms, which device is capable of returning plants which leave the transverse conveying channel back to said channel. The conveying device may be comprised of rolls or discs. It is effective only when the crop material has already left the conveying channel, and, in reverse mode, it cannot relieve any jam which may have developed. The subsequently published DE 103 14 859 A discloses a machine which is similar but has conveyors which rotate around a vertical axis which are disposed above the central cutting and intake mechanisms.
In U.S. Pat. No. 6,658,832, the guide element is attached to the bottom of the machine and ends abruptly at the rear side of the cutting and intake mechanisms. A rotatably mounted V-shaped roll is disposed over this location, which downwardly forces plant stalks which leave the transverse conveying channel. In reverse mode, in the event of a blockage, crop materials collect on the rear side of the guide element between the cutting and intake mechanisms which are close to the longitudinal mid-plane. The V-shaped roll is disposed an appreciable distance above the bottom of the machine, and thus is capable of only deflecting the upper parts of the plants, not the bottom parts of the stalks.
GB 2,012,154 A discloses a machine with only two cutting and intake mechanisms, with a guide element between them. In a plan view, it has a triangular shape, with a vertically downwardly extending rear wall. This machine can harvest only two rows at one time. Thus, one would not expect to even encounter the jamming problems which occur with the above-described machines which have greater operating width. An embodiment with a broader operating width is also illustrated, wherein the rear wall of the central guide element, disposed ahead of the intake channel of the field chopper, is oriented exactly transversely to the direction of travel. With this arrangement, it is again possible for a jam of materials to develop when in reverse mode.
Finally, U.S. Pat. No. 5,784,869 proposes a machine having intake chains, in which machine the plants are transported by a transverse screw conveyor. The bottom of the machine comprises a trough which partially surrounds the transverse conveying screw. A separator element, extending in the direction of travel, is disposed in the longitudinal mid-plane of the trough, which separator is intended to deflect the incoming crop material rearwardly. This machine has a configuration which fundamentally differs from the above-described machines.
The underlying problem of the present invention is deemed to be to devise a compact machine for mowing of stalk-like crop materials which eliminates or reduces the abovementioned drawbacks.